MONTPELIER — The Vermont National Guard says the United States Air Force has delayed the release of a final environmental impact statement on plans on where to base its next-generation fighter jet, the F-35, until the spring.

The Air Force says it needs to update the document to include 2010 census data for all six locations being considered.

The Vermont National Guard was notified on Wednesday evening. The delay will push back a decision on where the F-35s will be based.

The Air Force says it expects to start basing the F-35s at the first location in 2015.